Hydraulic tensioner lifter

Abstract

To provide a hydraulic tensioner lifter which can reduce the filling time of oil pressure into an oil chamber which is in a state wherein air is present therein and can sufficiently exhibit a vibration-damping function. A hydraulic tensioner lifter for applying tension to an endless power transmission band of a power transmission mechanism includes a plunger fitted for sliding movement in an accommodation hole of a tensioner body B and cooperating with the tensioner body B to define an oil chamber therebetween. An air-bleeder mechanism is provided for exhausting air in the oil chamber to the outside of the oil chamber. The purge valve P has a check valve function of permitting the exhaustion of the air in the oil chamber to the outside of the oil chamber but blocking admission of air into the oil chamber from the outside of the oil chamber and blocking discharging of the oil pressure in the oil chamber to the outside of the oil chamber. In addition, the volume of oil in the oil chamber may be decreased by a spring guide portion which is accommodated in the inside of the tensioner spring for guiding the tensioner spring.

1. A hydraulic tensioner lifter comprising:
 a tensioner body having an accommodation hole formed therein; 
 a plunger fitted for sliding movement in said accommodation hole and cooperating with said tensioner body to define an oil chamber therebetween; 
 a tensioner spring for biasing said plunger in an advancing direction; 
 a control valve for allowing an inflow of oil pressure into said oil chamber but blocking an outflow of the oil pressure from said oil chamber; and 
 an air-bleeder mechanism for exhausting air in said oil chamber to the outside of said oil chamber, wherein tension is applied to an endless power transmission band of a power transmission mechanism by said plunger advanced from said accommodation hole; 
 said air-bleeder mechanism includes a purge valve having an entrance positioned at an uppermost portion of said oil chamber and having a valving element for opening and closing an exhaust path for introducing air in said oil chamber to the outside of said oil chamber, and said purge valve has a check valve function of permitting an exhaustion of the air in said oil chamber to the outside of said oil chamber but blocking admission of the air into said oil chamber from the outside of said oil chamber and blocking a discharge of the oil pressure in said oil chamber to the outside of said oil chamber, 
 said purge valve including:
 an accommodation hole; 
 a first valve seat formed adjacent to an entrance path in the accommodation hole; 
 a second valve seat is formed on a discharge path side in the accommodation hole; 
 a valving element disposed between the first and the second valve seat in the accommodation hole; and 
 a spring biasing the valving element toward the first valve seat in a closing direction, 
 wherein a set load of said spring is set to a value such that, 
 when pneumatic pressure of the air in the oil chamber is pushed out into an inflow path and the entrance path by the oil pressure supplied into the oil chamber acts upon the valving element, the valving element is spaced away from the first oil seat to open the valve, and 
 when hydraulic pressure of the oil pressure supplied into the oil chamber and acting upon the valving element is higher than the pneumatic pressure, the valving element is seated on the second valve seat to close the valve. 
 
 
   
   
     2. The hydraulic tensioner lifter according to  claim 1 , wherein said purge valve is disposed in said tensioner body. 
   
   
     3. The hydraulic tensioner lifter according to  claim 2 , wherein the oil pressure flowing into said oil chamber is lubricating oil of an internal combustion engine, and an exit of said exhaust path is in communication with an internal space of said internal combustion engine. 
   
   
     4. The hydraulic tensioner lifter according to  claim 1 , wherein said purge valve is disposed outside said tensioner body and removably mounted on said tensioner body. 
   
   
     5. The hydraulic tensioner lifter according to  claim 4 , wherein the oil pressure flowing into said oil chamber is lubricating oil of an internal combustion engine, and an exit of said exhaust path is in communication with an internal space of said internal combustion engine. 
   
   
     6. The hydraulic tensioner lifter according to  claim 5 , wherein said exit of said exhaust path is in communication with said internal space through a conduit connected to said purge valve. 
   
   
     7. The hydraulic tensioner lifter according to  claim 1 , wherein the oil pressure flowing into said oil chamber is lubricating oil of an internal combustion engine, and an exit of said exhaust path is in communication with an internal space of said internal combustion engine. 
   
   
     8. The hydraulic tensioner lifter according to  claim 7 , wherein said exit of said exhaust path is in communication with said internal space through a conduit connected to said purge valve. 
   
   
     9. The hydraulic tensioner lifter according to  claim 1 , wherein the oil pressure flowing into said oil chamber is lubricating oil of an internal combustion engine, and an exit of said exhaust path is in communication with an internal space of said internal combustion engine. 
   
   
     10. A hydraulic tensioner lifter comprising:
 a tensioner body having a first body with a first accommodation hole and a second accommodation hole formed therein, said first and said second accommodation holes being separate from and parallel to each other; 
 a plunger fitted for sliding movement in first said accommodation hole and cooperating with said tensioner body to define an oil chamber therebetween; 
 a tensioner spring disposed in the inside of said plunger within said oil chamber for biasing said plunger in an advancing direction; 
 a control valve for allowing an inflow of oil pressure into said oil chamber and blocking an outflow of the oil pressure from said oil chamber, wherein tension is applied to an endless power transmission band of a power transmission mechanism by said plunger advanced from said first accommodation hole; and 
 a purge valve of an air-bleeder mechanism accommodated in said second accommodation hole of the first body, and 
 said plunger including a base member for fitting in said first accommodation hole and an end member integrally secured to said base member and forming an end portion of said plunger, said end member having a spring guide portion accommodated in the inside of said tensioner spring for guiding said tensioner spring, 
 wherein a cylinder axis has an inclined direction with respect to a horizontal plane, 
 the tensioner body being disposed in a position opposite to the inclined direction of the cylinder axis, 
 the purge valve being disposed above the plunger, and 
 the tensioner body having a tensioner side feed oil path. 
 
   
   
     11. The hydraulic tensioner lifter according to  claim 10 , wherein said tensioner lifter comprises a relief valve for discharging the oil pressure in said oil chamber to the outside of said tensioner lifter, and said relief valve has an entrance path which is open directly to said oil chamber and an exit path which is open directly to the outside of said tensioner lifter and is assembled as an integrated unit part to said tensioner body or said plunger. 
   
   
     12. The hydraulic tensioner lifter according to  claim 11 , wherein said end member is said relief valve assembled to said plunger. 
   
   
     13. The hydraulic tensioner lifter according to  claim 12 , wherein part of said control valve is accommodated inside of said plunger within an overall range of movement of said plunger. 
   
   
     14. The hydraulic tensioner lifter according to  claim 12 , wherein said tensioner body includes a second body, and said control valve is formed from said second body and is assembled as an integrated single unit part to said first body. 
   
   
     15. The hydraulic tensioner lifter according to  claim 11 , wherein part of said control valve is accommodated inside of said plunger within an overall range of movement of said plunger. 
   
   
     16. The hydraulic tensioner lifter according to  claim 10 , wherein part of said control valve is accommodated inside of said plunger within an overall range of movement of said plunger. 
   
   
     17. The hydraulic tensioner lifter according to  claim 16 , wherein said tensioner body includes a second body, and said control valve is formed from said second body and is assembled as an integrated single unit part to said first body. 
   
   
     18. The hydraulic tensioner lifter according to  claim 10 , wherein said tensioner body includes a second body, and said control valve is formed from said second body and is assembled as an integrated single unit part to said first body. 
   
   
     19. The hydraulic tensioner lifter according to  claim 11 , wherein said tensioner body includes a second body, and said control valve is formed from said second body and is assembled as an integrated single unit part to said first body. 
   
   
     20. The hydraulic tensioner lifter according to  claim 10 , wherein said tensioner lifter comprises a relief valve having an exit path for directly releasing oil pressure in said oil chamber to an oil path on the upstream side with respect to a valving element of said control valve, and said relief valve is assembled as an integrated single unit part to said tensioner body. 
   
   
     21. A hydraulic tensioner lifter comprising:
 a tensioner body having an accommodation hole formed therein; 
 a plunger fitted for sliding movement in said accommodation hole and cooperating with said tensioner body to define an oil chamber therebetween; 
 a tensioner spring for biasing said plunger in an advancing direction; 
 a control valve for allowing an inflow of oil pressure into said oil chamber but blocking an outflow of the oil pressure from said oil chamber; and 
 an air-bleeder mechanism for exhausting air in said oil chamber to the outside of said oil chamber, wherein tension is applied to an endless power transmission band of a power transmission mechanism by said plunger advanced from said accommodation hole; 
 said air-bleeder mechanism includes a purge valve having an entrance positioned at an uppermost portion of said oil chamber and having a valving element for opening and closing an exhaust path for introducing air in said oil chamber to the outside of said oil chamber, and said purge valve has a check valve function of permitting an exhaustion of the air in said oil chamber to the outside of said oil chamber but blocking admission of air into said oil chamber from the outside of said oil chamber and blocking a discharge of the oil pressure in said oil chamber to the outside of said oil chamber, wherein said purge valve is disposed outside said tensioner body and removably mounted on said tensioner body. 
 
   
   
     22. A hydraulic tensioner lifter comprising:
 a tensioner body having an accommodation hole formed therein; 
 a plunger fitted for sliding movement in said accommodation hole and cooperating with said tensioner body to define an oil chamber therebetween; 
 a tensioner spring disposed in the inside of said plunger within said oil chamber for biasing said plunger in an advancing direction; 
 a control valve for allowing an inflow of oil pressure into said oil chamber and blocking an outflow of the oil pressure from said oil chamber, wherein tension is applied to an endless power transmission band of a power transmission mechanism by said plunger advanced from said accommodation hole; and 
 a purge valve disposed outside said tensioner body and removably mounted on said tensioner body 
 said plunger including a base member for fitting in said accommodation hole and an end member integrally secured to said base member and forming an end portion of said plunger, said end member having a spring guide portion accommodated in the inside of said tensioner spring for guiding said tensioner spring.